title: Lipid transfer particle from the silkworm, Bombyx mori, is a novel member of the apoB/large lipid transfer protein family.
abstract: Lipid transfer particle (LTP) is a high-molecular-weight, very high-density lipoprotein known to catalyze the transfer of lipids between a variety of lipoproteins, including both insects and vertebrates. Studying the biosynthesis and regulation pathways of LTP in detail has not been possible due to a lack of information regarding the apoproteins. Here, we sequenced the cDNA and deduced amino acid sequences for three apoproteins of LTP from the silkworm (Bombyx mori). The three subunit proteins of the LTP are coded by two genes, apoLTP-II/I and apoLTP-III. ApoLTP-I and apoLTP-II are predicted to be generated by posttranslational cleavage of the precursor protein, apoLTP-II/I. Clusters of amphipathic secondary structure within apoLTP-II/I are similar to Homo sapiens apolipoprotein B (apoB) and insect lipophorins. The apoLTP-II/I gene is a novel member of the apoB/large lipid transfer protein gene family. ApoLTP-III has a putative conserved juvenile hormone-binding protein superfamily domain. Expression of apoLTP-II/I and apoLTP-III genes was synchronized and both genes were primarily expressed in the fat body at the stage corresponding to increased lipid transport needs. We are now in a position to study in detail the physiological role of LTP and its biosynthesis and assembly.
authors.affiliation: Division of Radiological Protection and Biology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Takeru
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Masashi
authors.initials: M
authors.lastname: Yuasa
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakudoh
authors.forename: Naoko
authors.initials: N
authors.lastname: Honda
authors.forename: Hajime
authors.initials: H
authors.lastname: Fugo
authors.forename: Kozo
authors.initials: K
authors.lastname: Tsuchida
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001055:Apolipoproteins B / Q000235:genetics*; D012831:Bombyx / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006031:Glycosylation; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009928:Organ Specificity; D010802:Phylogeny; D017385:Sequence Homology
chemical_list: D001055:Apolipoproteins B; D002352:Carrier Proteins; D018076:DNA, Complementary; D019476:Insect Proteins; C030363:lipid transfer protein
keywords: juvenile hormone-binding protein; lipid exchange and transport; lipophorin